Apparatus for crimping tow



Jan. 3, 1967 J. MYLO APPARATUS FOR CRIMPING TOW Filed March 9, 1964 FIG.2.

FIG.3.

INVENTOR. JOHN M YLO B; i & ATTORN Y United States Patent 3,295,180APPARATUS FOR CRIMPING TOW John Mylo, Athens, Ala., assignor to MonsantoCompany, a corporation of Delaware Filed Mar. 9, 1964, Ser. No. 350,4121 Claim. (Cl. 281) This invention relates to an apparatus for crimpingtextile fibers, and more particularly to an apparatus for continuouslyimparting a crimp in a thermoplastic tow without heating the same.

A quality which thermoplastic filaments initially lack is that ofinterfilament cohesion. After they have been formed and washed, thesurface thereof is very smooth, thereby preventing the yarn fromimmediately being used by the textile industry. In order to make thethermoplastic yarn more useful, the tow is crimped or textured. Thecrimping is generally done in the presence of heat so that when a tow issubjected to a deforming force, it will retain that shape after suchforce has been removed. Most crimping devices currently in use employ aconventional stuffing box in working association with nip rolls, weardiscs, clapper bars and the like. The crimp is produced mechanically byfeeding the fibers by feed rolls into a crimping chamber which isgenerally stuffed with fibers and maintained under a predetermined backpressure. Since the fibers still retain the heat supplied thereto whilein the stuifer box, the crimp which has been previously imparted by thecrimping gears is partially removed by the withdrawing rollers.Accordingly, to alleviate these and other problems, a primary object ofthis invention is to provide a yarn crimping apparatus which operatesefficiently in the absence of heat, crimping gears, stuffer boxes andthe like.

Another object of the present invention is to provide a yarn crimpingapparatus which is exceedingly simple and rugged so that it will havelong life and which also is very reliable in operation.

A further object of this invention is to provide a yarn crimpingapparatus which uses an adhesive-coated roller to crimp the yarn.

Still another object of this invention is to provide a yarn crimpingapparatus which imparts a crimp by sharply bending the tow back uponitself.

Other objects and advantages of this invention will become apparent whenthe following detailed description is read in conjunction with theappended drawings.

FIGURE 1 is a front pictorial view of the apparatus illustrating theprinciples of the invention and showing a pair of take-up rollersripping the tow from an adhesive roller; and

FIGURE 2 is a fragmentary side view of the apparatus of FIGURE 1illustrating the adhesive roller, the guide bar and showing the towbeing sharply bent back upon itself and the convolutions producedthereby.

FIGURE 3 is a blown-up view of a filament which is being crimped bycontinuously elongating the outer portion thereof in relation to theinner portion.

One embodiment of the present invention contemplates using an adhesiveroller to hold and position a tow for crimping. The crimp is permanentlyimparted to the filaments comprising the tow thereby aiding in theinterfilament resistance to slippage.

This crimping apparatus uses a roller having an adhesive cured thereonto provide a tacky surface. A press roll which is parallel to andcontiguous with the adhesive roller firmly presses a tow of filamentarymaterial against the adhesive roller so that each filament is adhesivelyheld thereon as the tow is rolled therebetween. The tow is carried bythe adhesive roller through an arc and is then pulled off the adhesiveroller by a pair of take-up rolls at a sharp angle. The take-up rollsthen move the crimped tow out of the crimping area.

As in most compositions, thermoplastic filaments have an inherenttensile strength. If a filament is bent, stretched or compressed belowthe yield point, the filament will behave as an elastic body and whenthe distorting force is removed it will return to its origin-a1 shape.If the filament is bent or stretched beyond its yield point, it retainsthat shape and is permanently deformed. This phenomenon is produced byhaving re-oriented the molecular arrangement of the filament. Whenforced beyond its yield point, the molecules remain in their re-orientedposition. In view of the above, a crimp may be imparted to the filamentsby bending them beyond their yield point thereby causing a permanentdeformation in the molecular structure of the tow.

The tow is held on the adhesive roller by an adhesive such as that foundon cellophane tape. Alternatively, an adhesive applicator may be used toapply a veneer of glue to the adhesive roller immediately before the towtangentially contacts the adhesive roller. The take-up rolls then pullthe tow off the adhesive roller at a sharp angle. Best results areobtained when the tow is pulled oif the adhesive roller at an angle ofabout The invention is illustrated in connection with the accompanyingdrawings in which the figures are illustrative of the preferredembodiment of the invention.

As shown, a tow 10, which is comprised of a plurality of filaments, isreceived and advanced by an adhesive roller 11 which has an adhesivethereon. A press roll 12, which is parallel to and in contiguous rollingarrangement with the adhesive roller 11, impinges the tow 10 against theadhesive roller 11 with a force sufiicient to securely cohere the tow 10to the adhesive roller 11. After the adhesive roller 11 rotates the tow10 beyond its acme, take-up rolls 13 and 14 which are parallel to eachother and perpendicular to the path of the tow 10 rip it from theadhesive roller 11 and remove it from the apparatus. The tow is thenpassed over a guide bar 22 which can also be used as a staticelectricity eliminator for removing any charges which may build upduring the process.

FIGURE 3 shows the manner in which the filaments in the tow are pulledoff the roller 11. Forces represented by arrows 20 pull the filament offthe roller 11 while forces represented by arrows 21 tend to retain thefilament in contact with the roller 11. There forces co-operate tostretch the outer edge of the filament. It can be seen that the amountof stretch X applied to one side of the filament is considerly less thanthe stretch X applied to the other side of the filament. The portion ofthe filament along the line X has been stretched beyond its yield pointand is there-by permanently deformed. Since one side of the filament islonger than the other, the filament convolutes into a helical or wavyconfiguration.

The amplitude of the crimp or waviness of the tow 10 can be increased bymore acuately pulling the tow 10 back over itself. The acute angle 15which is formed in tow 10 illustrates the desired inclination of thepath of the tow 10 from an imaginary tangent at that point with theadhesive roller 11.

To lay a veneer of glue on the surface of the adhesive roller 11, anadhesive collector roller 23 is partially submerged in a trough 16 inwhich the glue is stored. The adhesive collector roller 23 is in arolling arrangement with a planetary roller 17 and transfers the gluethereto. The planetary is also in a rolling arrangement with theadhesive applicator 18 which'in turn applies the glue to the adhesiveroller 11. Although some of these rollers may be eliminated by enlargingone roll or repositioning the adhesive applicator 18, the previouslydiscussed arrangement appears to be most satisfactory. Instead of usingthe adhesive applying arrangement shown, the roller 11 may be providedwith a layer of adhesive which is cured thereon to provide a tackysurface of some permanence.

While the preferred embodiment of this invention has been disclosed, itis to be understood that changes and variations may be made withoutdeparting from the spirit and scope of the invention as defined by theappended claim.

I claim:

Apparatus for crimping a tow of filamentary material comprising:

(a) a cylindrical roll mounted for rotational movement about an axis;

(b) an adhesive supply;

(c) means for transferring said adhesive in a thin layer to the lateralsurface of said cylindrical roll;

(d) a press roll mounted in juxtaposition to said cylindrical roll on anaxis parallel to said axis of said cylindrical roll whereby afilamentary tow fed between said cylindrical and press rolls willcontact and adhere to the adhesive on the lateral surface of saidcylindrical roll;

(e) a pair of take-up rolls mounted adjacent said cylindrical roll withtheir axes parallel to said axis of said cylindrical roll and with thenip between said take-up rolls disposed such that a line therethroughwill be parallel to a tangent to said lateral surface; and

(f) said cylindrical roll, press roll, and take-up rolls being relate-din such a manner that a flow of tow therebetween will :be along thelateral surface of said cylindrical roll to a point at which, under theinfluence of said take-up rolls, it is pulled back on itself at a sharpangle to thereby stretch the filaments on one side of the tow beyondtheir yield point so that said filamentary tow becomes crimped.

References Cited by the Examiner UNITED STATES PATENTS 1,664,319 3/1928Pellerin 264-168 1,914,869 6/1933 Rowe 264-283 X 2,030,156 2/1936 Rowe264--283 X 2,279,366 4/1942 Childs 264283 X 2,556,954 6/1951 Zeigler eta1. 264-283 X 3,177,556 4/1965 Van Blerk 2872 FOREIGN PATENTS 1,224,8612/ 1960 France.

ROBERT R. MACKEY, Primary Examiner.

